NER: Single Molecule Magnets for Quantum Computing

摘要题目：NER：单分子磁体用于量子计算我们提出了一项为期一年的纳米级探索性研究（NER），研究单分子磁体（SMM）在技术和基础上的重要领域，其在量子计算中的应用一直是人们激烈猜测的主题。SMM通常由2到15个磁性离子嵌入在非磁性配体基团中。每个SMM内部的磁相互作用强度在1-100K之间，而SMM之间的磁相互作用强度约为10mk，这些交换相互作用可能是铁磁的（FM）或反铁磁的（AFM）。虽然AFM SMM似乎比FM SMM表现出更有趣的低温量子效应，但后者已经引起了相当大的兴趣，因为它们的性质可能被用来构建有用的磁存储设备和量子计算机。实验研究最广泛的两种SMM， Fe8和Mn12，在SMM单元内具有多个自旋-自旋相互作用，包括FM和AFM符号，并且很难在理论上建模。然而，由于许多较小的SMM可以用由2-4个磁性离子组成的磁芯制成，我们建议初步研究由3-4个磁性离子组成的SMM在电子顺磁共振（EPR）结构中的磁相互作用的影响。该环境由强度为B0的恒定磁感应和频率为？的横向振荡磁感应组成。0和强度B1，并且可以用来研究SMM是否具有特殊的特性，这些特性可能允许人们使用包含大空间梯度的静态场读取和写入1-2 nm的信息。通过将这些量子结果与这些系统动力学的经典结果进行比较，通过各种时间相关函数进行测量，可以更好地理解更大的系统。这种精确可解的系统也将被研究，以研究振荡磁感应激发后SMM可能产生的退相干的严重性。这可以通过分析EPR线宽来研究。在这项探索性研究中获得的信息有望为开发可靠的数值方法来模拟更大的系统（如Fe8和Mn12）的行为提供必要的知识基础。拟议研究的一个重要成果将是在未来应用的探索性研究的前沿课题上教育和培训PI小组的初级成员。由于系统的简单性，研究结果将由PI用于一般教育目的，并向教育界广泛传播。

AbstractProposal No: 304665Title: NER: Single Molecule Magnets for Quantum ComputingWe are proposing a 1-year nanoscale exploratory research (NER) in the technologically and fundamentally important area of single molecule magnets (SMM) whose application in quantum computing has been the subject of intense speculation. The SMM's typically consist of 2 to 15 magnetic ions embedded in non-magnetic ligand groups. The magnetic interaction strengths within each SMM are in the range 1-100K, while that between SMM's is about 10 mK. These exchange interactions maybe ferromagnetic (FM) or antiferromagnetic (AFM). Although the AFM SMM's appear to exhibit more interesting low temperature quantum effects than do the FM SMM's, the latter have attracted a considerable interest, due to the suggestion that their properties might be exploited to construct useful magnetic storage devices and quantum computers. The two SMM's studied most extensively experimentally, Fe8 and Mn12, have multiple spin-spin interactions within a SMM unit, consisting of both FM and AFM signs, and are difficult to model theoretically. However, since a number of smaller SMM's can be made with magnetic cores that consist of as few as 2-4 magnetic ions, we propose to study initially the effects of the magnetic interactions within SMM's consisting of 3-4 magnetis ions in the electron paramagnetic resonance (EPR) configuration. This environment consists of a constant magnetic induction of strength B0 and a transverse oscillatory magnetic induction with frequency ?0 and strength B1, and can be used to investigate if the SMM's have special features that might allow one to read and write information on the scale of 1-2 nm using a static field that contains a large spatial gradient. By comparing these quantum results with the classical results for the dynamics of these systems, as measured by the various time correlation functions, better understanding would be possible for the larger systems. Such exactly solvable systems will also be studied to investigate the severity of the decoherence that can arise after a SMM has been excited by the oscillatory magnetic induction. This can be investigated by analyzing the EPR linewidths. The information obtained in this exploratory research is expected to provide the knowledge base necessary for developing reliable numerical methods to simulate the behavior of larger systems like Fe8 and Mn12 of more practical interest. A significant outcome of the proposed research will be the education and training of junior members of the PI's group in a subject at the forefront of exploratory research for future applications. Because of the simplicity of the systems, results of the research will be used by the PI for general educational purposes and broader dissemination to the educational community.